-LRB- CNN -RRB- -- Homeland security officials on Wednesday abruptly shelved a proposal to build a national database of license-plate scans after criticism from privacy advocates .

The proposal , which had been posted online last week by the office of Immigration and Customs Enforcement , sought a contractor who could establish a searchable database of license plates , with the times and locations where they were spotted by traffic cameras and other sources .

But in a statement late Wednesday , the department announced a reversal .

`` The solicitation , which was posted without the awareness of ICE leadership , has been canceled , '' said spokeswoman Gillian Christensen . `` While we continue to support a range of technologies to help meet our law enforcement mission , this solicitation will be reviewed to ensure the path forward appropriately meets our operational needs . ''

It was unclear whether the proposal was dead or was merely withdrawn for revisions .

Under the proposal , officers in the field would have been able to use their smartphones to look up a license plate and see every time and every place the vehicle had been spotted by a camera .

`` The database should track vehicle license plate numbers that pass through cameras or are voluntarily entered into the system from a variety of sources -LRB- access control systems , asset recovery specialists , etc. -RRB- and uploaded to share with law enforcement , '' the original solicitation read .

The proposed National License Plate Recognition database was to have been used by immigration officers to find and arrest fugitives .

Supporters of license-plate scanning , like former New York state homeland security chief Michael Balboni , said it could have been an invaluable tool for finding dangerous suspects .

`` What license-plate readers have been used for most effectively is -LRB- trying -RRB- to do hits against outstanding warrants , against unlicensed drivers , against folks who have shown before that they 've been involved in some kind of crime -- that 's where the hits come . ''

But since the solicitation was posted and featured in the Washington Post , privacy advocates have warned that the database sounded like a dragnet that would track the whereabouts of all drivers , including people who have done nothing wrong , and that the records might be held indefinitely .

`` The idea is , we want to collect everything on perfectly innocent people and then dip into it whenever we feel like it , '' said Kade Crockford of the American Civil Liberties Union . `` There have already been quite a few cases of abuse . Essentially , the problem is that this is creating a nationwide warrantless location-tracking list . ''

Opponents also said the tracking of cars would reveal personal information about drivers , like whether they went to church , where they slept at night , or whether they had been to an abortion clinic or a political protest .

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Immigration and Customs Enforcement sought bids for a license-plate tracking database

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Database would have been able to see where a vehicle 's plate had been captured on camera

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Tool would have helped law enforcement find criminals , one proponent says

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Database would have violated the privacy of innocent people , ACLU argues